Abrasive belt



mmm.. E

& 9

Sapt. 17, 1940.

INVENTOR. ERIC P. DAH LSTROM y ATTQRNEY;

Patentedept lZ, i I I s UN1.TE.D`TSTATES PATENT OFFICE e r B AS LI* EricPi Niagara Falls, assignor to The Carborudum Company, Niagara Falls,MY.,aco-porationotDelaware f Application December '9', 1938', Serial No.244, 795

' i jioain. (c.5 1's8) This invention' relates to abrasive belts "and oftwo straight lines 5 and 6,vwhich are of the. tothe method of'naking'the same. 'More parsame length. v 4 ticularly', it' relates 'tojoints or splices'in abrasive- The portion' o of abrasive coatedflexible mabelts and to the method of making said 'joints terial to bejoined tothe salient portion described' '5 or splice's. j i aboveis-illustrated in Figure 2, and, as shown r One object of the invention isto provide abrathere,` is formed with a boundary H that is resive beltshaving imp'roved joints or splices. Anentrant and complernentary to thesalient edge other object-is 'to' provide ta .methodofu making'2'described above. In this piece, the abrasive V improved'joints orsplices in abrasive belts., Other grain coating extends to the edge or.boundary objectswill become apparent from' the following ll of thereentrant edge. v a v disclosure.` r v I' r i g The abrasive-free area 3of thesalient 2 may In order that a full understanding of the inbevforme'd in various ways, but it has been found vention may be; had,reference is made to the to be convenient to remove the abrasive grainsappended drawing, in which from a fully coated sheet, that is, 'ajsheetin Figure 1 is a plan 1View of; a portion of coated which the abrasivegrain coating extends' fronl` abra'sive material designed for useinonewmodi edge to edge, by the careful application of a' fication of:the presentinvention; rotating abrasive wheel tothe part of the sheet-Figure 2 is a plan viewofa portion 'of abrasive thatis to be reed ofabrasive grains. y coated material adapted to adjoin the portion carefulapplication of a rotating` abrasive illustrated in Flgure 1; i i `wheelto the'abrasive coated sheet will remove 2 Figurea isa lan View of aportion oi' a' belt r the abrasivegrains and most or substantially all eembodying one. modification( of the" present inof' the a'dhesive withoutdamagin'g theflexible yention in which the portions separatelyiliusbackingmaterial; i v trate'd in Figures 1 and"2 are shown joined;The abrasive-free area 3 at the salientedge Figure 4 is anenlargedcross-sectional'view, of theapiece l ltiirtbendprot idedktheuncoated 25 along the:line IV.- IV of Figure 3, 01 a portionof area iscoa a hes ve o the desired 4 a belt ernbodyingthe modificationiliustrated in character and the piece o with the reentrant F'igureifter, the sections shown' in'` Figures 1 arg i complementry C(legge isplacted on -tip ofathe and ve been placed in juxtaposition but arasive-freean a' esive coa ed por on so beiore the two sections' havebeen obinpresed that the abrasive boundary 4 of the salient piece 30flrmly togsether to iorn aclse strcnfjoint; b I anid'the bunday lltcfthtehreetranpiec ;g

Figure ,is a'p'an v ew o 'a por ion of a elt are' n regis er an so a e eges an erbodying another modificationaof the present line up in astraight line on one side and the invention; r ees zzdand 2?lie-pdiatraigit line o'n the r '35 Flgure 6 is a plan view of a portionof a belt o er si e, as ilus ra e e i The overembod'ying still anothermodification oi the preslapped portions of the two-pieces are thenpressed ent invention; and' e v a ;together and held so that they cannotmove while Figure 7 isa plan view of'a portion of a`be1t he d v iSsettingv 'embodyingstill another modification'ot the presv Figur& Showsin eleYation an'enlarged w m t :mesazh tiul'ii i In making a belaccording to e mo fica ion V v ot (the present invention illustrated inFigures the Place 5 Show? b in i e contact 2, a andt'ga' pieceofabrasive coated flexible With thbackmg the piece These back' materialI of sitable Size ;prevpred the ings may be of any su table flexiblematerial, such e e a as paper, cloth, fibre, metal or other fiexibleJoning operation by Iorminga salient edge 2 e d f a d mg sheet materal01 of any suitable combination of p m s 3 r e a two or more of suchmaterialsin laminated form. swe miting in e W? yv 9 t #went edge- InFigure &thejont is-shown'after the two end v Als umtmtd' theahmsve'ree F3:15 mund' portions of'thebelt have been. placed in juxtaed e e 2 of hMeriton e d n position but beforethe final pressure is put on 0 by hedge 7 O h abrasivey m u i h: 15 them to force them into moreintimateirelation- :i ii:: zzszuzzeagii e e gure 's ows a p an view of amodified belt salient illustrsted in Figures 1, 3 and 4 is tormed jointmade according to the present inventio', by the inter-section, at thecenter line of the belt, where the salient end portion is angular, butthe 55 the crown pulleys, and sometimes serves to deter the belt from atendency to track sideways ofl' the pulleys.

Figura 6 shows a plan view of a further modification of the presentinvention where the apex of the salient portion of the belt end isnotsharp and angular but where the apex portion has been rounded ofi toremove the angular intersection portion of the salient. This 'shape canbe used to advantage where the belt formed passes over certain types ofpulley shapes.' V

Figure 7 shows a plan view of a still ifurther modification of thepresent invention where the salient end portion of the belt is in theshape of a semicircle. In this modification a straight line cannot bedrawn which will fall on the line of junctl'on of the belt ends, butwill always merely cross the joint, since' the direction of the joint`is constantly changing. This efiect is obtained while still retainingall the advantages of a salient joint and the Construction of thepresent "invention( r The joints shown in Figures 5, 6 a'nd'7 are alllikewise formed in the manner set forth in' connection with the beltportions shown in-Figures 1 to 4. i

`Belts possessing joints or splices made according to the presentinvention possess numerous advantagesover belts jointed by the methodsheretofore used. Heretofore belt joints have either been made so thatthe line of joning between two adjacent belt ends laid eitherperpendicularto the line of movement of the belt or in a singledirection oblique thereto. Slight variations in this procedure have beento give such joints an i irregularity by curving or otherwisezig-zag'ging or serrating the line 'of joining in order to strengthenthe joint. However, by the present invention of a joint wherein the endof one belt section has a contour such that the central portion of theend boundary is protruding or salient with respect to the portions ofthe end boundary at either side thereto, and the second or adjoiningsection has a complementary re-entrant shaped end, a belt is obtained ofimproved running characteristics. By the use of such belt joints thebelt is given what might be termed an automaticoscillating effect. Asthe belt joint of the present invention passes over the crown pulleythere is a tendency to draw toward the center. Then as the splice orjoint leaves the crown, it may tend to track one way or another,depending upon the alignment of the remaining pulleys; but as the spliceagain goes over the' crown, it .again tends to center itself. Thisefi'ect is of particular value in the use of wide belts. Minor itendencies to track to one side or the other can often be counteractedby proper alignmentof the pulleys but in cases where it is impossible toobtain suitable' adjustment of the pulleys to cause the belt to tracksatisfactorily it is' found that the belt splice of the presentinvention serves to give a centering of the belt by the above-explained2,215,2o 4 I, I j automatic oscillating action in a highly s atisfactory way.

Furthermore, by still retaining an oblique direction of the joint withrespect to the movement of the belt the belt is caused to run smoothlyand with little or no vibration since the joint is grad ually presentedunder the work instead of suddenly appearing.

A further decided advantage of thepresent invention is its Simplicity ofconstruction of .the belt joint or splices. Previous efforts to obtain abelt having similar Operating advantages have led to `cumbersome andtime-wasting methods of jointure. Resort has been had to constructionswhereby the end portion need be slotted for inthe use of complicatedjoint structures involving I sertion of the abutting end section, ortongue or i tab arrangements have beenused, which tabs or tongues haveto be interlocked or fitted together. The present' invention avoidsthese manufacturing disadvantages in a very simple but ingenious V wayby formingthe two 'end sections into a'salient and' a correspondingcomplementary re entrant shaped end section, sklving the abrasive from.theend edge portion of the salient section and joining the two in themanner previously described in detail. The salient section is mucheasier to clear of abrasivefrom the portion `borderingthe end withoutinjury to the adjacent abrasive' areas than is removal of abrasivefromthe re-entrant portion. Therefore in the making of belts there is adecided saving of time and a lower number of rejections of belts due todefects in the joint;

A further, advantage of the belt joint of the present inventionresides'inthe fact that when in Operating the belt is run in a directionso that the joint approaches the* work with the apex' foremost, in otherwords, the belts as' illustrated'in.

formedfrom a single abrasive strip with the ends jointed, it isparticularly well adapted to forming extra wide 'belts from a number ofpieces of abrasivematerial where thewidth; of the belt'is greater thanthe width of the original abr'asive strips, thus necessitating the useof numerous pieces of abrasive sheet material `joined in several places.

Other advantages are readily discerniblefupon consideration of theinvention herein set forth.

Having described my invention in its preferred embodiment I do notwishto limit myself other .than by the scope of the appended claim.

I claim: i i i p In anabrasive belt, a joint between adjoin'ing portionswhich comprises a plurality of layers'in juxtaposition and adhesivelyunited,`the under layervbeing bounded at the juncture by a salient edgeand being free of abrasive material in the area bounded by said salientedge and a'line of substantially the same contourbut spaced apartthere'from, the upper layer being bounded' at the juncture by an edge"which is re-entrant and compl'ementary to the salient edge of the lowerlayer. ERICP, DAHLSTROM.

